Nickel for Scale is a Processing application that can be used to automatically resize 3D models of physical objects.

Nickel for Scale resizes objects using computer vision by finding a nickel (something of known size) in a scene, and then letting the user measure something else in that scene.  Nickel for Scale has been used to successfully resize 3D models of rings to an individual's finger and then print these resized models on a MakerBot Cupcake CNC.

Nickel for Scale was developed as a small step towards exploring the new kinds of customization possible with modern prototyping tools.  This movement has interesting implications for users who are currently stuck with one-size-fits-many products and assistive technologies.  The customization offered by Nickel for Scale offers new opportunities for individuals with changing needs such as children, older adults, and individuals with motor impairments.

Nickel for Scale was developed over the course of 48 hours by Marty McGuire and Amy Hurst in November 2010 during the first Baltimore Hackathon, where it was voted Audience Favorite. It demonstrates that usable customization tools can be built quickly and with low-cost commodity hardware.  Nickel for Scale would not be possible without the hard work of the folks behind Processing, OpenCV, OpenSCAD, unlekkerLib, controlP5, and ReplicatorG.

So what are you waiting for? Grab the source on GitHub!